C-terminal Binding Proteins (CtBP) 1 and 2 operate as transcriptional coregulators that modulate numerous cellular processes including repressing genes involved in genome stability, epithelial differentiation and apoptosis. Substantial evidence implicates CtBP in multiple human cancers. CtBP contains a functional enzymatic domain, providing substrate, coenzyme and adjacent pockets, which is both highly unusual among transcription factors and potentially valuable for inhibitor design. Our crystallographic analysis of CtBP1 and CtBP2 has revealed unique details of the active site that we have already used in structure based drug design to develop the highest affinity CtBP inhibitor identified to date. We have assembled an interdisciplinary team with strengths structural biology, structure based drug design, cancer biology and medicinal chemistry to extend these studies. Our project will use computational analysis of the binding sites to identify potential inhibitors; those identified will be screened by enzymatic and biophysical techniques to determine binding affinity and crystallographic analysis to determine the stereochemistry of binding. These results will inform novel chemical synthesis to develop additional inhibitors. We will also investigate the role of oligomerization and catalysis in CtBP transcriptional function to inform additional inhibitor design and synthesis studies. These studies are directed at understanding CtBP structure and function at a level that will lead to inhibitors that can serve as important molecular probes in the study of CtBP in cancer and, eventually, to the development of highly selective anti-neoplastic CtBP inhibitors.